Field of the Invention
The present invention relates to a resin composition for golf balls and to golf balls in which such a composition is used. The invention relates in particular to a golf ball resin composition suitable for use as the cover material in a golf ball having a core of one or more layer and a cover of one or more layer, and to a golf ball in which such a composition is used.
Prior Art
Three-piece solid golf balls and four-piece solid golf balls that employ a urethane cover instead of an ionomer cover have come to be widely used recently among professional golfers and skilled amateurs. The purpose for doing so is to achieve not only a good distance on shots with a driver, but also to further extend the distance on shots with a middle iron such as a number six iron (I#6) and to optimize the spin rate on approach shots so as to achieve a good controllability. In addition, another important challenge is properly gauging and controlling the distance traveled by the ball on approach shots around the green at a distance of about 15 yards.
Controllability on approach shots around the green at a distance of about 15 yards depends not only on the spin rate of the golf ball, but also to a large degree on the initial velocity of the ball at launch. While there may be a variety of ways among different players for adjusting the distance traveled by a golf ball, the distance of a golf ball is usually controlled by modulating the take-back and follow-through on the swing so as to adjust the force of impact. Professional golfers and skilled amateurs in particular, as they themselves explain, control the distance of the ball while sensing the force delivered to the ball during the time that the ball and the clubface are in contact from impact to follow-through. Also, although golf balls made with a urethane cover have a high rebound, which extends the distance on shots with a driver, on approach shots, they are in contact with the clubface for only a short time and thus have a tendency to fly off too quickly. Hence, on approach shots, the force delivered to the ball is difficult for the golfer to gauge, which tends to make the distance traveled by the ball difficult to control. In other words, what professional golfers and skilled amateurs desire is to more easily sense the force delivered to the ball during the interval in which the clubface and the ball are in contact, so that distance control is easier. Furthermore, making it easier to gauge the distance of the ball on approach shots around the green gives the golfer more of an edge in playing the game.
Golf balls provided with a urethane cover so as to impart good spin receptivity have been proposed in the past in order to improve controllability on approach shots. One example is the art disclosed in JP-A 2006-312044. In addition, golf balls provided with a soft urethane cover so as to be even more receptive to spin have been disclosed in, for example, JP-A 2013-9814. However, on approach shots, both of these golf balls are too lively at takeoff, making the distance difficult to gauge.
It is therefore an object of this invention to provide a golf ball resin material and golf ball which makes the force delivered to the ball while the ball and the clubface are in contact from impact to follow-through easier to feel, facilitating distance control of the ball, and which has an excellent controllability on approach shots with, for example, a sand wedge (SW) around the green at a distance of about 15 yards.